To have a lucid dream you need to be aware that you're dreaming. It's known to be a difficult feat to achieve since upon the slightest realization that you're dreaming, you're most likely going to wake up.
Recently, it's incredibly easy for me to have one. I dream about my father every single day. He's there, together with the family. And every single night, I'm 100% sure they are dream. Father is not here anymore and I'll never forget about that. Nevertheless, I couldn't woke up. I don't want to. Only here can I talk to him - to apologize for the promise that I could never fulfill.
And so every night I have a lucid dream.